The invention relates to the fields of wastes treatment and disposal. In particular, the invention relates to the use of iodine complexes in combination with gelling agents to produce strong disinfectants which not only physically stabilize biohazardous and infectious wastes but also kill pathogens contained in the wastes.
Wastes, particularly infectious human wastes, present a vast array of health problems for humans. For example, wastes may contain viral, bacterial, and fungal contaminants that may be spread to human and animal populations through such pests as mosquitoes and flies. One area of concern to humans is the spread of infectious diseases when such diseases are generated in medical environments such as hospitals and clinics. Blood borne pathogens such as hepatitis B and HIV viruses may be found in blood, urine, and other bodily fluids found in medical environments. Theses fluids, although ultimately disposed of, present dangers not only to those who may come into direct contact with the wastes during generation of the waste, such as hospital personnel and patients, but also workers involved with the disposal of the waste.
Various methods have been devised to treat medical wastes including the use of disinfectants and antimicrobial agents. However, even with the use of these agents, prior to and even after treatment, workers may still be exposed when wastes spill, leak or aerosolize from their containers. Accordingly, in order to prevent such mishaps workers have developed methods to contain the wastes by using solidifying and gelling agents.
One problem encountered by workers who handle contaminated liquid wastes is that these wastes are generally treated and disposed of using disinfectants. For example, phenol has been used in combination with gelling agents. Specifically ortho-benzyl-para-chlorophenol is used in combination with a gelling agent such as starch grafted polyacrylate. This composition is poured into canisters containing liquid wastes and the liquid turns into a highly viscous gelatin-like substance. Of course, many of these agents pose general questions and concerns regarding their toxicity and potential of environmental harm.
Iodine has been used as a biocide for many years. Iodine has several properties that make it difficult to use alone as a biocide. For example, iodine is insoluble in water. Also, when placed in volatile solutions such as in alcohols, the concentration of the iodine varies due to evaporation of the alcohol. High concentrations of iodine can lead to severe irritation of the skin.
In an effort to overcome these problems, workers developed an anti-microbial composition comprising polyvinyl pyrrolidone polymer, in combination with iodine (xe2x80x9cPVP-I). Polyvinyl pyrrolidone and iodine, when combined in an aqueous solution, form a complex. The major complex formed is a triiodide. Some of the iodine reacts with water and is reduced to iodide. Some of the iodine also becomes covalently linked to the carbon atoms of the polyvinyl pyrrilidone. It is generally accepted that the anitmicrobial activity of PVP-I arises from the release of elemental iodine (free iodine) in solution. In solution, the triiodide species is in equilibrium with iodine and Iodide. Accordingly, pH, concentration, and temperature play an important role in antimicrobial properties of any PVP-I solution.
PVP-I solutions have been used in the medical industry as a disinfectant and is provided in topical cleaners. It is also used as a scrub and with swabs. Crosspovidone-iodine has also been impregnated onto cellulose filters.
One noted drawback to the use of PVP-I is that it is known to be unstable at low pH. Heretofore, attempts to combine gelling agents with disinfecting agents have not produced a superior product having good gelling properties while maintaining an effective disinfectant qualities.
Accordingly, it is an object of the present invention to not only provide a composition that disinfects wastes which contain a high organic (e.g., proteins) load but one that also provides adequate gelling or solidifying properties.
Provided herein is a composition comprising: (a) polyvinylpyrrolidone; (b) iodine; and (c) a gelling agent.
Also provided by the present invention is a composition comprising: (a) polyvinylpyrrolidone; (b) iodine; and a (c) gelling agent; wherein the composition is provided in an amount that is effective in killing a pathogen in a liquid waste containing blood and the composition contains sufficient quantity of polyvinylpyrrolidone and iodine such that when a sufficient amount of the composition is added to 90 grams of a liquid waste containing blood the weight of the combined weight of the polyvinylpyrrolidone and the iodine composition is greater than 0.3% of the total weight of the waste containing the composition. The upper concentration of the composition in the waste is the saturation level of the gelling agent preferably, the total weight of the composition in solution is no more than 10% of the total weight of the solution containing the composition.
Further provided herein is a composition comprising: (a) polyvinylpyrrolidone, (b) iodine; and (c) a gelling agent and the composition is provided in an amount that is effective in killing a pathogen in a liquid waste containing blood and wherein the weight of the composition is such that when added to a liquid waste containing blood, is less than or equal to 10%, by weight, of the total weight of the waste containing the composition and the amount of the combined weight of polyvinylpyrrolidone and iodine is such that when the composition is added to a liquid waste containing blood, is greater than 0.3% of the total weight of the waste containing the composition.
The pathogens that are killed by the present invention include bacterial and viruses that are hazardous to animals including humans.
The composition surprisingly provides a 6 log kill (microbial) in 24 hours, preferably in about 8 hours, most preferably in about 4-6 hours.
In one aspect of the invention, the concentration, in a liquid waste, of the composition is in the range, by weight, of 0.3% up to about 10%, preferablyfrom 0.3% to about 5%, most preferably at about 4% The composition provides superior and unexpected gelling and solidifying properties at low pH. Preferably, the pH of the solution containing the composition is less than 6, preferably less than or equal to about 4.
A further embodiment of the invention is provided comprising a method of treating liquid waste comprising: adding polyvinyl pyrrolidone, iodine, and a gelling agent to an aqueous waste stream such that the concentration of the combined weight of the polyvinylpyrrolidone and iodine is greater than 0.3%, by weight, of the total weight of the waste, polyvinylpyrrolidone, iodine and gelling agent.
The methods may be modified by addition of elements of compositions described herein.
The wastes streams best treated using embodiments of the present invention include animal wastes, preferably liquid human medical wastes generated for example during surgery.
Another embodiment of the present invention is provided herein comprising a system for treating liquid waste stream having: (a) an aqueous waste comprising human liquid waste; (b) a polyvinylpyrrolidone and iodine complex wherein the concentration of the complex is, by weight of the total weigh of the system, greater than 0.3%; and (c) a gelling agent.
The gelling agent used in the present invention comprises a superabsorbent composition. Preferably, the gelling agents of the preferred present invention comprise acrylate polymers based on the terpolymer of acrylic acid, sodium acrylate and a cross-linker. These gelling agents are superabsorbents and include crosslinked polymers of acrylate or methacrylate monomers and a crosslinking agent such as crosslinkers including di- and tri acrylate esters such as 1,1,1-trimethylolpanetriacrylate, N,Nxe2x80x2-methylenebisacrylamide, triallyamine, ethyleneglycoldiacrylate, tetraerthlyeneglycoldicacyrlate, trimethylolpropanetriacrylate and the methylate of any of the above mentioned acrylates. These polymers include hydrophilic esters of acrylic or methacrylic acid (e.g., 2-hydroxyethylmethacrylate and its analogs). A preferred example is an hydroxyethyl(meth)acrylate hydrogel.
The super absorbents also include ionogenic monomers such as acrylic and methacrylic acid (or their sodium salts) and a cross linker. One example includes poly(acrylic acid) hydrogels.
Other polymerization additives may be employed in the invention. These include mercapto compounds, formic acid, carbon tetrachloride, isopropanol, monobasic sodium phosphate and hypophosphite salts.
Examples of superabsorbent polymers that may be used in the present invention include Stockhausen""s AP(copyright) acrylate series (e.g., AP(copyright) 75, AP(copyright) 80, AP(copyright) 80 HS AP(copyright) 80 HSB, AP(copyright) 85, AP(copyright) 85-13, AP(copyright) 85-38). The chemical basis for the series being the sodium salt of crosslinked polyacrylic acid, in some cases containing a polyalcohol.
Other superabsorbent materials that may be used in the present invention include polyacrylic acid polymers such as those represented by Carbopol(copyright) Resins (e.g., Types, 907, 910, 941, 934, 934P and 940, having approximate molecular weights of 450,000, 750,000, 250,000, 3,000,000, 3,000,000 and 4,000,000 respectively).
Another embodiment of the present invention includes Medi-Gel(copyright) 100 superabsorbent polymer comprising: potassium polyacrylate, lightly crosslinked (92% to 98%); water (2% to 8%); hydrophobic silicon dioxide, amorphous (0% to 3%) and acrylic acid ( less than 0.08%).
Preferably the gelling agents are provided in a dry composition such that the weight of the gelling agent is greater than about 65% of the total weight of the composition.
In the present invention, a polyvinylpyrrolidone is complexed with iodine. Preferred complexes include PVP-I 30/06, PVP-I FC 1026. PVP-I 30/06 means that the K value of the PVP is 30 and 06 is loss of iodine in % during storage conditions of a 10% PVP-I solution held for 15 hours at 80xc2x0 C. The 30/06 product comprises an iodine content between 9.0% and 12.0% (on a dry basis). The nitrogen content is not less than 9.5% and not more than 11.5% (on a dry basis).
The PVP-I FC 1026 differs from the 30/06 product in that 16-18% free iodine is available (on a dry basis) and the nitrogen content is 8.5 to 9.6% (on a dry basis).
Preferred compositions of the present invention comprise a combination of ingredients such that the concentration, by weight, of the polyvinyl pyrrilidone and iodine, in a aqueous solution containing ten percent or less, by weight, of the composition is from about 0.4 to 0.5% to about 0.7 to 0.8%, most preferably about 0.5% to about 0.7%.
In another embodiment of the invention, the gelling composition comprises a combination of ingredients such that the concentration, by weight, of the polyvinyl pyrrilidone and iodine, in a aqueous solution containing ten percent or less, by weight, of the composition is greater than 0.3% to about 1%.
Acids may also be included in the invention in amounts up to 10% of the total weight of the composition, preferably less than 1%. Preferred acids are those that can be provided in powder form at room temperatures such as citric, boric, and phosphoric acids.
Iodate salts may also be used in the invention. The preferred amount of iodate salt used is less then 0.5%. Potassium iodate is the preferred iodate salt used in the present invention.
It is preferred that the PVP-iodine, potassium iodate and acrylic polymer, be mixed in a large batch format.
Initial work performed on polyacrylates in solution (e.g., 20-24 grams PVP-I (1.9%) and 40 grams of potassium polyacrylate in 1200 milliliters 0.9% NaCl did not achieve a 1xc3x97106 kill (e.g., Bacillus subtillis) within 24 hours. The pH of the solution was between 5-6, that is, a buffered aqueous solution containing PVP-I 30/06, saline solution and a buffer had a pH of about 5-6 prior to the addition of the gelling agent. It was concluded that when using potassium polyacrylate the formulations would be unstable or that poor gelling would occur at low pH. A low pH is desirable in order to achieve a preferable free iodine concentration of about 0.2% in solution. Accordingly, aqueous solutions of PVP-I and potassium polyacrylate having a combined concentration in solution of about 5.1% (1.9% PVP-I) was not effective in solutions having a pH at about and having free iodine concentrations at about were not effective in killing microbes.
The most preferred use of the present invention is in hospital room canisters used to capture bodily fluids suctioned during surgery.